1. Field of the Invention
The present invention relates to a display device, and more particularly to a display device with a discharge lamp in which the illumination region of the discharge lamp may vary with varying voltage or frequency of discharge power to be supplied to the discharge lamp so as to display information with dynamic effect.
2. Description of the Prior Art
U.S. patent application Ser. No. 299,613 filed by the applicant of the present invention discloses a discharge lamp formed by a glass tube which serves as a dielectric body and having a pair of electrodes one of which is provided within the glass tube and the other is outside of the glass tube. The discharge lamp can be activated for luminous discharge by relatively low power supply having the voltage peak of hundreds of volts and the frequency between several and tens kHz. Thus, such a discharge lamp has made it possible to provide a display device which is compact in size and light in weight and suitable for displaying characters, numerals, symbols, etc. In the above prior art display system, specific information can be blinked, for example, by supplying discharge power to the discharge lamp intermittently at every given period of time so that the information may be distinct from others. Such a system, however, blinks the discharge lamp itself at every given period of time and cannot directly create a dynamic effect on the information by a single discharge lamp. Such a dynamic effect may be created on the information, for example, by employing a number of discharge lamps arranged in series which are flashed sequentially one by one. This system will, however, require a specific timing control circuit to supply discharge power for flashing the individual discharge lamp at a given time, leading to a large-sized construction of the overall system. This disadvantage will remarkably spoil facility of this type of the display device of the prior art.